Network services across non-contiguous subnets of a label switched network separated by a non-label switched network

ABSTRACT

In a first enclave of a label switching network (LSN), a protocol data unit (PDU) of the LSN is formatted to include a network service field specifying a service to be applied to the PDU. The service field can be positioned between PDU data link layer and network layer fields. The PDU specifies PDU routing/forwarding information for a path in the LSN ending in an LSN second enclave, and routing/forwarding for a destination between path segments in a non-LSN. The PDU is communicated from the first enclave, via the non-LSN, to the second enclave in accordance with the routing/forwarding information for the destination between path segments in the non-LSN. In the second enclave, each network service specified for the PDU is determined and then applied to the PDU. The second enclave transmits the network serviced PDU from the second enclave in accordance with the routing/forwarding information of the PDU in the label switching network.

TECHNICAL FIELD

The disclosed technology relates to providing network services acrossnon-contiguous subnets of a label switched virtual private network. Inparticular, example embodiments relate to providing per tenant networkservices across enclaves of a Multiprotocol Label Switching (MPLS)network spanning an Internet Protocol (IP) network.

BACKGROUND

MPLS is a technology to direct digital data packets over computernetworks based on path labels, rather than based on network addressessuch as IP addresses. Each path label, also known as a “virtual privatenetwork” (VPN) label, identifies a path between network nodes, ratherthan only identifying the endpoints of the packet transmission. Routersof an MPLS network must be enabled to perform label switching to routeand forward the packets. Such routers in the interior of an MPLS networkare know as “label switch routers,” while such routers at the ingressand egress points of the MPLS network are known as “label edge routers.”Label edge routers discover and interface with non-MPLS networks outsidethe MPLS network using protocols such as Border Gateway Protocol (BGP).The outside networks can be provider networks, such as a nationalbroadband provider IP networks, in which case the provider's routers areknown as provider edge (PE) routers. The use of labels enables each MPLSrouter to maintain a separate routing and forwarding table instance,known as a virtual routing and forwarding (VRF) table or forwardinginformation base (FIB), for each of a plurality of tenants of the MPLS.

Generic Routing Encapsulation (GRE) is a point-to-point tunnelingprotocol in which two peer nodes form the endpoints of the tunnel. GREis designed to encapsulate network-layer (L3) packets inside IPtunneling packets. Multi-point GRE (mGRE) is a similar protocol with asingle endpoint at one side of the tunnel connected to multipleendpoints at the other side of the tunnel. An mGRE tunnel can provide acommon link between branch offices that connect to the same VPN.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram depicting a communications and processingarchitecture to provide network services across non-contiguous subnetsof a label switched virtual private network, in accordance with certainexample embodiments.

FIG. 2 is a block flow diagram depicting a method to provide networkservices across non-contiguous subnets of a label switched virtualprivate network, in accordance with certain example embodiments.

FIG. 3 is a block flow diagram depicting a method to format a protocoldata unit (PDU) of a label switching network to include a networkservice field specifying at least one network service to be applied tothe PDU, in accordance with certain example embodiments.

FIG. 4 is a portion of a PDU used to provide network services acrossnon-contiguous subnets of a label switched virtual private network, inaccordance with certain example embodiments.

FIG. 5 is a block flow diagram depicting a method to format a PDU of alabel switching network to include a network service field specifying atleast one network service to be applied to the PDU, in accordance withcertain example embodiments.

FIG. 6 is a portion of a PDU used to provide network services acrossnon-contiguous subnets of a label switched virtual private network, inaccordance with certain example embodiments.

FIG. 7 is a diagram depicting a computing machine and a module, inaccordance with certain example embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS Overview

Implementing an MPLS VPN over GRE or mGRE (MPLSoGRE) can overcome therequirement that all subnets participating in an MPLS network supportMPLS. MPLSoGRE overcomes this requirement by allowing MPLS connectivitybetween non-contiguous MPLS subnets (hereinafter also referred to asMPLS “enclaves”) that are connected by non-MPLS networks, such as IPnetworks. MPLSoGRE allows MPLS label switched paths (LSPs) to use GREtunnels to cross non-MPLS routing areas, autonomous systems, andInternet service providers (ISPs). For this reason, MPLSoGRE is beingdeployed to build large-scale private MPLS VPN networks comprisingnon-contiguous subnets over public IP transport. The MPLSoGREfunctionality offers customers the scale and functions of MPLS VPN labelforwarding networks, while leveraging the simplicity of public IPtransport. The Internet Engineering Task Force (IETF) Request ForComment (RFC) 4797 describes an implementation strategy for such anetwork.

However, neither IETF RFC 4797, nor any other known publication,describes implementations for transporting network services informationor policy information across non-contiguous MPLS subnets separated byone or more non-MPLS networks using MPLSoGRE. For example, an MPLSnetwork operator might want to apply a policy that packets originatingfrom a source node in a first enclave of the MPLS network pass through acloud-based firewall network service in a second enclave of the MPLSnetwork before being transmitted to a destination in a third enclave ofthe MPLS network.

Embodiments herein provide computer-implemented methods, systems, andcomputer program products for applying service chaining (and in somecases, the propagation of other metadata such as security data) toMPLSoGRE networks encompassing multiple enclaves separated by a non-MPLSnetwork.

In some embodiments, in a first enclave of a label switching network,network computing device(s), such as a label edge router, format aprotocol data unit (PDU) of the label switching network to include anetwork service field. The network service field specifies at least onenetwork service to be applied to the PDU. The PDU specifies routing andforwarding information of the PDU for a path in the label switchingnetwork ending in an enclave of the label switching network other thanthe first enclave, and routing and forwarding information betweenenclaves in a non-label switching network. The network service field ispositioned between the PDU data link layer and network layer of thenon-label switching network. The label edge router communicates theformatted PDU from the first enclave, via the non-label switchingnetwork, to a second enclave of the label switching network inaccordance with the routing and forwarding information between enclavesin the non-label switching network.

In the second enclave of the label switching network, a receiving routersuch as a label edge router of the second enclave, determines eachnetwork service specified to be applied to the PDU in the second enclavefrom the network service field of the communicated PDU. Computingdevices of the second enclave apply each of the determined networkservices to the PDU. Computing devices of the second enclave, forexample, a second enclave edge router, transmit the network serviced PDUin accordance with the routing and forwarding information of the PDU inthe label switching network.

By using and relying on the methods and systems described herein, thetechnology disclosed herein provides for service chaining acrossnon-contiguous subnets of a label switched computer network. As such,the technologies described herein may be employed to implementper-tenant and non-static service chains while retaining the benefits ofa label-switched network and the benefits of inter-subnet transportusing pervasive broadband non-label switched networks. The technologydescribed herein can be used to leverage the availability of cloudnetwork services (which are typically isolated in a cloud subnet) totransport data between label switched subnets. Hence, users of suchtechnology avoid, among other things, static one-size-fits-allapplication of network services, the duplication of identical networkservices in each subnet, and cumbersome routing and forwarding schemesto link data with network services.

These and other aspects, objects, features, and advantages of theexample embodiments will become apparent to those having ordinary skillin the art upon consideration of the following detailed description ofillustrated example embodiments.

Turning now to the drawings, in which like numerals represent like (butnot necessarily identical) elements throughout the figures, exampleembodiments are described in detail.

Example System Architectures

In example architectures for the technology, while each server, system,and device shown in the architecture is represented by one instance ofthe server, system, or device, multiple instances of each can be used.Further, while certain aspects of operation of the technology arepresented in examples related to the figures to facilitate enablement ofthe claimed invention, additional features of the technology, alsofacilitating enablement of the claimed invention, are disclosedelsewhere herein.

FIG. 1 is a block diagram depicting a communications and processingarchitecture 100 to provide network services across non-contiguoussubnets of a label switched virtual private network, in accordance withcertain example embodiments. As depicted in FIG. 1, the architecture 100includes label switching network enclaves 110, 120, and 130, along withservice provider network 150 (a non-label switched network). In acontinuing example, label switching enclaves 110 and 130 representdifferent physical subnets of a customer's non-contiguous MPLS network,while enclave 120 represents an MPLS enclave implemented by a serviceprovider as a cloud service 160 for a customer. Each MPLS enclave 110,120, and 130 includes at least one customer edge device—112, 122, and132, respectively. Each customer edge device 112, 122, and 132 (and byextension, each enclave 110, 120, and 130) is associated with one ormore VRF tables (for example, 118, 128, and 138, respectively) forallowing multiple concurrent instances of a routing table to existwithin the device at the same time. In particular, each of enclaves 110,120, and 130 include a copy of VRF A 118, 128, and 138, respectively.The service provider network 150, a non-label switched network, includesprovider edge devices 152, 154, and 156 to communicate with customeredge devices 112, 122, and 132, respectively.

In the continuing example, each customer edge device 112, 122, and 132is a label edge router implementing a version of the Border GatewayProtocol (BGP) to communicate with the corresponding service providernetwork 150 provider edge device (also implementing BGP). In someembodiments, other edge protocols, such as Exterior Gateway Protocol(EGP) can be used. Throughout this specification, “communicate” refersto the ability both to “transmit” and to “receive.”

Each of label switching enclaves 110, 120, and 130, along with serviceprovider network 150, includes one or more wired or wirelesstelecommunications systems including at least one label switched networksuch as an MPLS and generalized MPLS (which extends MPLS to managefurther classes of interfaces and switching technologies other thanpacket interfaces and switching, such as time division multiplexing,layer-2 switching, wavelength switching and fiber-switching) by whichnetwork devices may exchange data in formats known as protocol dataunits (PDUs), packets, or frames. For example, the service providernetwork 150 may include one or more of a local area network (LAN), awide area network (WAN), an intranet, an Internet, a storage areanetwork (SAN), a personal area network (PAN), a metropolitan areanetwork (MAN), a wireless local area network (WLAN), a virtual privatenetwork (VPN), a cellular or other mobile communication network, aBLUETOOTH® wireless technology connection, a near field communication(NFC) connection, any combination thereof, and any other appropriatearchitecture or system that facilitates the communication of signals,data, and/or messages.

Throughout the discussion of example embodiments, it should beunderstood that the terms “data” and “information” are usedinterchangeably herein to refer to text, images, audio, video, or anyother form of information that can exist in a computer-basedenvironment.

Each network device can include a communication subsystem capable oftransmitting and receiving data over the network(s) it communicateswith. For example, each network device can include a server, or apartition of a server, router virtual machine (VM) or container, aportion of a router, a desktop computer, a laptop computer, a tabletcomputer, a television with one or more processors embedded thereinand/or coupled thereto, a smart phone, a handheld computer, a personaldigital assistant (PDA), or any other wired or wireless processor-drivendevice. In some embodiments, a user associated with a device mustinstall an application and/or make a feature selection to obtain thebenefits of the technology described herein.

The network connections illustrated are examples and other approachesfor establishing a communications link between the computers and devicescan be used. Additionally, those having ordinary skill in the art andhaving the benefit of this disclosure will appreciate that the networkdevices illustrated in FIG. 1 may have any of several other suitablecomputer system configurations, and may not include all the componentsdescribed above.

In example embodiments, the network computing devices, and any othercomputing machines associated with the technology presented herein, maybe any type of computing machine such as, but not limited to, thosediscussed in more detail with respect to FIG. 7. Furthermore, anyfunctions, applications, or components associated with any of thesecomputing machines, such as those described herein or any others (forexample, scripts, web content, software, firmware, hardware, or modules)associated with the technology presented herein may by any of thecomponents discussed in more detail with respect to FIG. 7. Thecomputing machines discussed herein may communicate with one another, aswell as with other computing machines or communication systems over oneor more networks, such as network 110, 120, 130, and 150. Each networkmay include various types of data or communications network, includingany of the network technology discussed with respect to FIG. 7.

Example Embodiments

The example embodiments illustrated in the following figures aredescribed hereinafter with respect to the components of the exampleoperating environment and example architecture 100 described elsewhereherein. The example embodiments may also be practiced with other systemsand in other environments. The operations described with respect to theexample processes can be implemented as executable code stored on acomputer or machine readable non-transitory tangible storage medium(e.g., floppy disk, hard disk, ROM, EEPROM, nonvolatile RAM, CD-ROM,etc.) that are completed based on execution of the code by a processorcircuit implemented using one or more integrated circuits. Theoperations described herein also can be implemented as executable logicthat is encoded in one or more non-transitory tangible media forexecution (e.g., programmable logic arrays or devices, fieldprogrammable gate arrays, programmable array logic, application specificintegrated circuits, etc.).

Referring to FIG. 2, and continuing to refer to FIG. 1 for context, ablock flow diagram depicting a method 200 to provide network servicesacross non-contiguous subnets of a label switched VPN is shown, inaccordance with certain example embodiments. In such a method 200, in afirst enclave of a label switching network (such as enclave 110), one ormore computing devices (such as the CE router 112) formats a protocoldata unit (PDU) of a label switching network to include a networkservice field specifying at least one network service to be applied tothe PDU—Block 210. The computing device(s) formats the PDU to specifyrouting and forwarding information of the PDU for a path in the labelswitching network ending in an enclave of the label switching networkother than the first enclave. The computing device(s) format the PDU tospecify routing and forwarding information between enclaves in anon-label switching network. The network service field is positionedbetween the PDU data link layer and network layer of the non-labelswitching network.

In a continuing example, an MPLS network operator applies a policy thatpackets originating from a source node (for example source node 114) inthe first enclave 110 of the MPLS network pass through a cloud-basedfirewall 124 in the second enclave 120 of the MPLS network, before beingtransmitted to a destination (for example, destination 134) in the thirdenclave 130 of the MPLS network. In such a case, customer edge (CE)router 112 in enclave 110 formats the PDU to include the provision ofcloud firewall services 124. The CE router 112 also formats a label ofthe MPLS network to indicate a path to destination 134 in enclave 130using a VPN label corresponding to the path from source 114, throughfirewall 124, and to destination 134, using the instance of VRF A 118associated with customer edge device 112. In other examples, a networkelement of enclave 110 other than the CE router 112, for example asecurity policy routine executing on source 114, formats the PDU tospecify that one or more services are to be applied to the PDU atcertain points in the path.

Referring to FIG. 3, and continuing to refer to prior figures forcontext, a block flow diagram 300 depicting the operation of Block 210is shown, in accordance with certain example embodiments (including thecontinuing example). In such methods, the second network is an InternetProtocol (IP) datagram network, and the network service field describesnetwork service chaining using a network service header (NSH). NSHprovides a service plane protocol for metadata exchange along a servicepath to specify services to be applied to a packet/frame/PDU. Theservices can include security functions (for example a firewall or anintrusion detection system), network acceleration and optimization, andserver load balancing. Applying a sequence of services is known as“service chaining” or “service function chaining.” Implementations ofNSH are described in IETF draft-ietf-sfc-nsh-05 (current version as ofthe filing date of the present application).

In the continuing example, as part of the Block 210, the CE router 112formats the PDU with a generic routing encapsulation (GRE) field of theservice provider network 150 (an IP network) ahead of the networkservice header (NSH) field—Block 312. Referring to FIG. 4, a portion ofa PDU 400 used to provide network services across non-contiguous subnetsof a label switched virtual private network is shown, in accordance withexample embodiments, including the continuing example. In the continuingexample, the CE router 112 formats the GRE field 410 in accordance withIETF RFC 2784, including formatting a GRE IP Header 412 with the serviceprovider network 150 IP address of provider edge router 154—the PErouter providing access to the enclave hosting the service to be appliedto the PDU. The CE router determines this address from the serviceinformation (a firewall of enclave 120 served by PE router 154 describedbelow). CE router 112 learns of the IP address of provider edge router154 via a border gateway protocol (BGP) operating between the serviceprovider IP network 150 and each CE router of MPLS enclaves 110, 120,and 130. CE router 112 formats the GRE header 414 of the GRE field 410to indicate that the encapsulated protocol is type 0x894F—correspondingto NSH. The CE router 112 places the GRE field 410 ahead of the NSHfield 420 in the PDU.

In addition, as part of Block 210, the CE router 112 formats an MPLSlabel of the label switching network (LSN) as a context header in theNSH field—Block 314. In the continuing example, the CE router 112formats the NSH field 420 per IETF draft-ietf-sfc-nsh-05 to specify aservice path identifier (SPI), a service index (SI), a next protocol(NP), and at least two context headers (one context header for eachservice to be applied to the PDU, and one for the MPLS VPN path labelfor the path between the source 114 and the destination 134). In thecontinuing example shown in FIG. 4, the combination SPI/SI (10/255)corresponds to a transport layer of type GRE—as described above. The NPvalue shown in the body of field 420, “MLS,” indicates that the contextheader 426, and not the following fields 430 and 440, will contain MPLSdata in addition to containing service function chain (SFC) data. The NPvalue 422 (shown outside the body of field for clarity) 420 indicatesthat the fields 430 and 440 following the NSH field 420 are IPv4protocol fields. The metadata type field 424 (0x1) (shown outside thebody of field for clarity) 420 indicates that NSH 420 contains fixedlength context headers. The first context header 426 carried by the NSH420 is the MPLS VPN label for the path from the source 114 in the firstenclave 110 to the destination 134 in the third enclave 130. The secondcontext header 428 a identifies the firewall service 124 of enclave 120as the service to be applied—it is from this data that the CE router 112formatted the GRE label 410. The NSH 420 can include additional fieldsfor the application of additional services, for example context header Nspecifying service Y to be applied to the PDU after application ofservice 1 (the firewall 124). In the continuing example, only oneservice, the firewall 124, is applied to the PDU.

Returning to FIG. 2, and continuing to refer to FIG. 3 and FIG. 4 forcontext, the one or more computing devices (such as the CE router 112,PE router 152, service provider network 150, PE router 154, and CErouter 122) communicate the formatted PDU from the first enclave, viathe non-label switching network, to a second enclave of the labelswitching network, in accordance with the routing and forwardinginformation between enclaves in the non-label switching network—Block220. In the continuing example, the CE router 112 transmits PDU 400 fromenclave 110, via PE router 152 and service provider network 150, to thePE router 154 and CE router 122 in accordance with the routing andforwarding information contained in the GRE field 410. PE routers 152and 154 do not examine the NSH fields—hence the NSH and MPLS data issaid to be “encapsulated” by the GRE data and is said to be communicatedover the service provider network 150 through a GRE “tunnel” between PErouter 152 and PE router 154. The static BGP routing between the CErouter 112 and PE router 152, and then PE router 154 and the CE router122, ensures that the PDU is forwarded to the CE router 122. Beforeforwarding the PDU to the CE router 122, the PE router 154 strips theGRE data from the PDU, leaving the NSH 420 as the next field to beprocessed. The CE router 122 receives the PDU minus the GRE fieldapplied by CE router 112.

In the second enclave of the label switching network, the one or morecomputing devices (such as CE router 122), determines, from the networkservice field of the communicated PDU, each network service specified tobe applied to the PDU—Block 230. In the continuing example, in enclave120, CE router 122 determines, from NSH 420 internal next protocol (NP)value that the first context header 426 “MLS” will contain MPLS data inaddition to containing service function chain (SFC) data. The firstcontext header 426 carried by the NSH 420 is the MPLS VPN label 426 forthe path from the source 114 to the destination 134. The CE router 122examines the second context header 428 a to determine that the serviceto be applied to the PDU, before routing the PDU on the path indicatedin the VPN label 426, is the firewall service 124.

The computing device(s) applies, in the second enclave, each of thedetermined network services to the PDU—Block 240. In the continuingexample, the CE router 122 of the second enclave 120 forwards the PDU,now stripped of the GRE header applied by the CE router 112 of the firstenclave 110, to the firewall 124 for network service processing. Whilethe specific operation of the firewall 124 is outside the scope of thisapplication, firewall 124 may use several strategies to control trafficflowing in the MPLS network, including analyzing PDU/packet contents forfeatures such as paths and addresses, comparing packetmeta-characteristics to profiles of allowed and prohibited packets. Insome embodiments, firewall 124 is integrated in to CE router 112. Insome embodiments, the CE router forwards the PDU to a router closer tothe firewall 124. In the continuing example, the firewall examines theVPN label 126, and determines that the PDU is allowed to pass todestination 134 from source 114 because the VPN label is on a whitelistof labels in the MPLS. Such information is propagated between networkservices by technologies known to those of skill in the relevant art,and is outside the scope of this application. In other embodiments,network services such as intrusion prevention, or load balancing areapplied to the PDU based upon the service specified in the context fieldof the NSH 420. For some such services, higher-level protocol data ofthe PDU, such as transport, session, presentation, and application datacan be examined as part of applying the network service.

Upon completion of the network services specified to be applied in thereceiving enclave, the PDU is transmitted in accordance with the labelswitched network routing and forwarding information of the PDU—Block250. In the continuing example, the Firewall 124 is an NSH-awareservice, and upon completion of the service strips the firewall NSHcontext field 428 a from the NSH field 420, and returns the PDU to theCE router 122 of the second enclave 120 for determination of the nextstep in the communication of the PDU from the source 124 to thedestination 134. In other embodiments, the second enclave router nearestthe firewall 124, for example a label switch router of the enclave,strips the firewall NSH context field from the PDU and determines thepath from the VPN label. In the continuing example, CE router 122 of thesecond enclave 120 examines the context headers of the NSH field 420,and determines 1) that there are no more services to be applied to thePDU, and 2) that the VPN label indicates a path to a destination inenclave 130. In some embodiments, a service audit trail is maintained bynot stripping the context header of a completed service, but indicatingin the context header that the service has been completed. For example,the service sets a “completed” flag in the corresponding context header.

In the continuing example, similar to Block 210, CE router 122, throughexamination of the VPN label in PDU 400 showing a path to destination134 in enclave 130, and through CE router's participation in the MPLSnetwork and the IP network (through BGP), determines that the PDU mustbe routed to enclave 130 via a GRE tunnel from PE router 154 to PErouter 156. The CE router 122 of the second enclave 120, then adds a newGRE label, in the same fashion as described above with regard to Blocks210, 412, and 414, to the PDU for transport of the PDU from the secondenclave 120 to the third enclave 130. At the third enclave, CE router132 received a PDU stripped of the newly added GRE field, examines theNSH field 420. Since the NSH field 320 either contains no context fieldsrequiring the application of network services, or contains an indicationthat network services have been applied to the PDU, forwards the PDU toits destination per the MPLS VPN label 426 contained in the NSH field420.

In other embodiments, MPLS VPN labels can be stacked. For example, afirst enclave 110 router can apply a stack of MPLS VPN labels, such aVPN label 426, to the NSH field 420 of a packet intended for adestination in a third enclave 130 via a second enclave 120 whereservices, such as firewall 124, specified in the NSH 460 are to beapplied. When the end of the path of the topmost label in the stack isreached, the node directing the PDU reads the next label in the stackand acts on the packet as described above.

Referring to FIG. 5, and continuing to refer to prior figures forcontext, a block flow diagram 500 depicting the operation of Block 210is shown, in accordance with certain example embodiments (including asecond example). In such methods, the second network is an InternetProtocol (IP) datagram network, and the network service field describesnetwork service chaining using a network service header (NSH).

In the second example, as in the first example, an MPLS network operatorapplies a policy that packets originating from a source node (forexample source node 114) in the first enclave 110 of the MPLS networkpass through a cloud-based firewall 124 in the second enclave 120 of theMPLS network, before being transmitted to a destination (for example,destination 134) in the third enclave 130 of the MPLS network. In such acase, customer edge (CE) router 112 in enclave 110 formats the PDU toinclude the provision of cloud firewall services 124. The CE router 112also formats a label of the MPLS network to indicate a path todestination 134 in enclave 130 using a VPN label corresponding to thepath from source 114, through firewall 124, and to destination 134,using the instance of VRF A 118 associated with customer edge device112.

In the second example, as part of the Block 210, the CE router 112formats the PDU with a generic routing encapsulation (GRE) field of theservice provider network 150 (an IP network) ahead of the networkservice header (NSH) field—Block 512. Referring to FIG. 6, a portion ofa PDU 600 used to provide network services across non-contiguous subnetsof a label switched virtual private network is shown, in accordance withexample embodiments, including the second example. In the secondexample, the CE router 112 formats the GRE field 610 in accordance withIETF RFC 4023, including formatting a GRE IP Header 612 with the serviceprovider network 150 IP address of provider edge router 154—the PErouter providing access to the enclave hosting the service to be appliedto the PDU. The CE router determines this address from the serviceinformation (a firewall of enclave 120 served by PE router 154 describedbelow). CE router 112 learns of the IP address of provider edge router154 via a border gateway protocol (BGP) operating between the serviceprovider IP network 150 and each CE router of MPLS enclaves 110, 120,and 130. CE router 112 formats the GRE header 614 of the GRE field 410to indicate that the encapsulated protocol is type 0x8847—correspondingto a multicast frame, the GRE field 410, carrying the MPLS VPN label. CErouter 112 formats an MPLS VPN label 616 of the label switching networkwithin the GRE field 610 for the path between the source 114 and thedestination 134. The CE router 112 places the GRE field 410 ahead of theNSH field 420 in the PDU.

In addition, as part of Block 512, the CE router 112 formats the NSHfield 620 as described in connection with FIG. 3 and FIG. 4 above. Thetechnology of the second example then proceeds with Blocks 220-250 asdescribed above, except that the VPN label 616 in the second embodimentis examined by the receiving router, CE router 122 in the case of thesecond example, before determining the services specified in the NSH620, and then re-inserted by CE router 122 into the next GRE header forthe non-MPLS segment of the path from PE router 154 to PE router 156.

Other Example Embodiments

FIG. 7 depicts a computing machine 2000 and a module 2050 in accordancewith certain example embodiments. The computing machine 2000 maycorrespond to any of the various computers, servers, mobile devices,embedded systems, or computing systems presented herein. The module 2050may comprise one or more hardware or software elements configured tofacilitate the computing machine 2000 in performing the various methodsand processing functions presented herein. The computing machine 2000may include various internal or attached components, for example, aprocessor 2010, system bus 2020, system memory 2030, storage media 2040,input/output interface 2060, and a network interface 2070 forcommunicating with a network 2080.

The computing machine 2000 may be implemented as a conventional computersystem, an embedded controller, a laptop, a server, a mobile device, asmartphone, a set-top box, a kiosk, a vehicular information system, onemore processors associated with a television, a customized machine, anyother hardware platform, or any combination or multiplicity thereof. Thecomputing machine 2000 may be a distributed system configured tofunction using multiple computing machines interconnected via a datanetwork or bus system.

The processor 2010 may be configured to execute code or instructions toperform the operations and functionality described herein, managerequest flow and address mappings, and to perform calculations andgenerate commands. The processor 2010 may be configured to monitor andcontrol the operation of the components in the computing machine 2000.The processor 2010 may be a general purpose processor, a processor core,a multiprocessor, a reconfigurable processor, a microcontroller, adigital signal processor (DSP), an application specific integratedcircuit (ASIC), a graphics processing unit (GPU), a field programmablegate array (FPGA), a programmable logic device (PLD), a controller, astate machine, gated logic, discrete hardware components, any otherprocessing unit, or any combination or multiplicity thereof. Theprocessor 2010 may be a single processing unit, multiple processingunits, a single processing core, multiple processing cores, specialpurpose processing cores, co-processors, or any combination thereof.According to certain embodiments, the processor 2010 along with othercomponents of the computing machine 2000 may be a virtualized computingmachine executing within one or more other computing machines.

The system memory 2030 may include non-volatile memories, for example,read-only memory (ROM), programmable read-only memory (PROM), erasableprogrammable read-only memory (EPROM), flash memory, or any other devicecapable of storing program instructions or data with or without appliedpower. The system memory 2030 may also include volatile memories, forexample, random access memory (RAM), static random access memory (SRAM),dynamic random access memory (DRAM), and synchronous dynamic randomaccess memory (SDRAM). Other types of RAM also may be used to implementthe system memory 2030. The system memory 2030 may be implemented usinga single memory module or multiple memory modules. While the systemmemory 2030 is depicted as being part of the computing machine 2000, oneskilled in the art will recognize that the system memory 2030 may beseparate from the computing machine 2000 without departing from thescope of the subject technology. It should also be appreciated that thesystem memory 2030 may include, or operate in conjunction with, anon-volatile storage device, for example, the storage media 2040.

The storage media 2040 may include a hard disk, a floppy disk, a compactdisc read only memory (CD-ROM), a digital versatile disc (DVD), aBlu-ray disc, a magnetic tape, a flash memory, other non-volatile memorydevice, a solid state drive (SSD), any magnetic storage device, anyoptical storage device, any electrical storage device, any semiconductorstorage device, any physical-based storage device, any other datastorage device, or any combination or multiplicity thereof. The storagemedia 2040 may store one or more operating systems, application programsand program modules, for example, module 2050, data, or any otherinformation. The storage media 2040 may be part of, or connected to, thecomputing machine 2000. The storage media 2040 may also be part of oneor more other computing machines that are in communication with thecomputing machine 2000, for example, servers, database servers, cloudstorage, network attached storage, and so forth.

The module 2050 may comprise one or more hardware or software elementsconfigured to facilitate the computing machine 2000 with performing thevarious methods and processing functions presented herein. The module2050 may include one or more sequences of instructions stored assoftware or firmware in association with the system memory 2030, thestorage media 2040, or both. The storage media 2040 may thereforerepresent examples of machine or computer readable media on whichinstructions or code may be stored for execution by the processor 2010.Machine or computer readable media may generally refer to any medium ormedia used to provide instructions to the processor 2010. Such machineor computer readable media associated with the module 2050 may comprisea computer software product. It should be appreciated that a computersoftware product comprising the module 2050 may also be associated withone or more processes or methods for delivering the module 2050 to thecomputing machine 2000 via the network 2080, any signal-bearing medium,or any other communication or delivery technology. The module 2050 mayalso comprise hardware circuits or information for configuring hardwarecircuits, for example, microcode or configuration information for anFPGA or other PLD.

The input/output (I/O) interface 2060 may be configured to couple to oneor more external devices, to receive data from the one or more externaldevices, and to send data to the one or more external devices. Suchexternal devices along with the various internal devices may also beknown as peripheral devices. The I/O interface 2060 may include bothelectrical and physical connections for operably coupling the variousperipheral devices to the computing machine 2000 or the processor 2010.The I/O interface 2060 may be configured to communicate data, addresses,and control signals between the peripheral devices, the computingmachine 2000, or the processor 2010. The I/O interface 2060 may beconfigured to implement any standard interface, for example, smallcomputer system interface (SCSI), serial-attached SCSI (SAS), fiberchannel, peripheral component interconnect (PCI), PCI express (PCIe),serial bus, parallel bus, advanced technology attached (ATA), serial ATA(SATA), universal serial bus (USB), Thunderbolt, FireWire, various videobuses, and the like. The I/O interface 2060 may be configured toimplement only one interface or bus technology. Alternatively, the I/Ointerface 2060 may be configured to implement multiple interfaces or bustechnologies. The I/O interface 2060 may be configured as part of, allof, or to operate in conjunction with, the system bus 2020. The I/Ointerface 2060 may include one or more buffers for bufferingtransmissions between one or more external devices, internal devices,the computing machine 2000, or the processor 2010.

The I/O interface 2060 may couple the computing machine 2000 to variousinput devices including mice, touch-screens, scanners, electronicdigitizers, sensors, receivers, touchpads, trackballs, cameras,microphones, keyboards, any other pointing devices, or any combinationsthereof. The I/O interface 2060 may couple the computing machine 2000 tovarious output devices including video displays, speakers, printers,projectors, tactile feedback devices, automation control, roboticcomponents, actuators, motors, fans, solenoids, valves, pumps,transmitters, signal emitters, lights, and so forth.

The computing machine 2000 may operate in a networked environment usinglogical connections through the network interface 2070 to one or moreother systems or computing machines across the network 2080. The network2080 may include wide area networks (WAN), local area networks (LAN),intranets, the Internet, wireless access networks, wired networks,mobile networks, telephone networks, optical networks, or combinationsthereof. The network 2080 may be packet switched, circuit switched, ofany topology, and may use any communication protocol. Communicationlinks within the network 2080 may involve various digital or analogcommunication media, for example, fiber optic cables, free-space optics,waveguides, electrical conductors, wireless links, antennas,radio-frequency communications, and so forth.

The processor 2010 may be connected to the other elements of thecomputing machine 2000 or the various peripherals discussed hereinthrough the system bus 2020. It should be appreciated that the systembus 2020 may be within the processor 2010, outside the processor 2010,or both. According to certain example embodiments, any of the processor2010, the other elements of the computing machine 2000, or the variousperipherals discussed herein may be integrated into a single device, forexample, a system on chip (SOC), system on package (SOP), or ASICdevice.

Embodiments may comprise a computer program that embodies the functionsdescribed and illustrated herein, wherein the computer program isimplemented in a computer system that comprises instructions stored in amachine-readable medium and a processor that executes the instructions.However, it should be apparent that there could be many different waysof implementing embodiments in computer programming, and the embodimentsshould not be construed as limited to any one set of computer programinstructions. Further, a skilled programmer would be able to write sucha computer program to implement an embodiment of the disclosedembodiments based on the appended flow charts and associated descriptionin the application text. Therefore, disclosure of a particular set ofprogram code instructions is not considered necessary for an adequateunderstanding of how to make and use embodiments. Further, those skilledin the art will appreciate that one or more aspects of embodimentsdescribed herein may be performed by hardware, software, or acombination thereof, as may be embodied in one or more computingsystems. Additionally, any reference to an act being performed by acomputer should not be construed as being performed by a single computeras more than one computer may perform the act.

The example embodiments described herein can be used with computerhardware and software that perform the methods and processing functionsdescribed previously. The systems, methods, and procedures describedherein can be embodied in a programmable computer, computer-executablesoftware, or digital circuitry. The software can be stored oncomputer-readable media. For example, computer-readable media caninclude a floppy disk, RAM, ROM, hard disk, removable media, flashmemory, memory stick, optical media, magneto-optical media, CD-ROM, etc.Digital circuitry can include integrated circuits, gate arrays, buildingblock logic, field programmable gate arrays (FPGA), etc.

The example systems, methods, and acts described in the embodimentspresented previously are illustrative, and, in alternative embodiments,certain acts can be performed in a different order, in parallel with oneanother, omitted entirely, and/or combined between different exampleembodiments, and/or certain additional acts can be performed, withoutdeparting from the scope and spirit of various embodiments. Accordingly,such alternative embodiments are included in the scope of the followingclaims, which are to be accorded the broadest interpretation so as toencompass such alternate embodiments.

Although specific embodiments have been described above in detail, thedescription is merely for purposes of illustration. It should beappreciated, therefore, that many aspects described above are notintended as required or essential elements unless explicitly statedotherwise.

Modifications of, and equivalent components or acts corresponding to,the disclosed aspects of the example embodiments, in addition to thosedescribed above, can be made by a person of ordinary skill in the art,having the benefit of the present disclosure, without departing from thespirit and scope of embodiments defined in the following claims, thescope of which is to be accorded the broadest interpretation so as toencompass such modifications and equivalent structures.

1. A computer-implemented method, comprising: in a first enclave of alabel switching network, formatting, by one or more computing devices, aprotocol data unit (PDU) of the label switching network to include anetwork service field specifying at least one network service to beapplied to the PDU, wherein the PDU specifies routing and forwardinginformation of the PDU for a path in the label switching network endingin an enclave of the label switching network other than the firstenclave, and routing and forwarding information between enclaves in anon-label switching network; communicating, by the one or more computingdevices, the formatted PDU from the first enclave, via the non-labelswitching network, to a second enclave of the label switching network inaccordance with the routing and forwarding information between enclavesin the non-label switching network; in the second enclave of the labelswitching network: determining, by one or more computing devices, fromthe network service field of the communicated PDU, each network servicespecified to be applied to the PDU in the second enclave; applying, bythe one or more computing devices, each of the determined networkservices to the PDU; and transmitting, by the one or more computingdevices, the network-serviced PDU in accordance with the routing andforwarding information of the PDU in the label switching network.
 2. Themethod of claim 1, wherein the non-label switching network is anInternet Protocol (IP) network, and wherein the network service fielddescribes network service chaining.
 3. The method of claim 2, whereinthe label switching network is a MultiProtocol Label Switching (MPLS)network, and wherein the network service field is formatted as a networkservice header (NSH).
 4. The method of claim 3, wherein formattingcomprises: formatting a generic routing encapsulation (GRE) field of thenon-label switching network ahead of the NSH field; and formatting anMPLS label of the MPLS VPN as a context header in the NSH field.
 5. Themethod of claim 3, wherein formatting comprises formatting a genericrouting encapsulation (GRE) field of the non-label switching network,including an MPLS label of the MPLS VPN, ahead of the NSH field.
 6. Themethod of claim 1, wherein the at least one network service comprises atleast one of a firewall, a load balancer, an intrusion preventionsystem, and a traffic analyzer.
 7. The method of claim 1, wherein thenetwork service field is positioned between the PDU data link layer andnetwork layer of the non-label switching network.
 8. A computer programproduct, comprising: a non-transitory computer-readable storage devicehaving computer-executable program instructions embodied thereon thatwhen executed by a computer cause the computer to apply packet-levelnetwork services across enclaves of a label switched network separatedby a non-label switched network, the computer-executable programinstructions comprising: computer-executable program instructions toformat, in a first enclave of a label switching network, a protocol dataunit (PDU) of the label switching network to include a network servicefield specifying at least one network service to be applied to the PDU,wherein the PDU specifies routing and forwarding information of the PDUfor a path in the label switching network ending in an enclave of thelabel switching network other than the first enclave, and routing andforwarding information between enclaves in a non-label switchingnetwork; computer-executable program instructions to communicate theformatted PDU from the first enclave, via the non-label switchingnetwork, to a second enclave of the label switching network inaccordance with the routing and forwarding information between enclavesin the non-label switching network; in the second enclave of the labelswitching network: computer-executable program instructions to determinefrom the network service field of the communicated PDU, each networkservice specified to be applied to the PDU; computer-executable programinstructions to apply each of the determined network services to thePDU; and computer-executable program instructions to transmit thenetwork serviced PDU in accordance with the routing and forwardinginformation of the PDU in the label switching network.
 9. The computerprogram product of claim 8, wherein the non-label switching network isan Internet Protocol (IP) datagram network, and the network servicefield describes network service chaining.
 10. The computer programproduct of claim 9, wherein the label switching network is aMultiProtocol Label Switching (MPLS) network, and the network servicefield is formatted as a network service header (NSH).
 11. The computerprogram product of claim 10, wherein formatting comprises formatting ageneric routing encapsulation (GRE) field of the non-label switchingnetwork ahead of the NSH field; and formatting an MPLS label of the MPLSVPN as a context header in the NSH field.
 12. The computer programproduct of claim 10, wherein formatting comprises formatting a genericrouting encapsulation (GRE) field of the non-label switching network,including an MPLS label of the MPLS VPN, ahead of the NSH field.
 13. Thecomputer program product of claim 8, wherein the at least one networkservice comprises at least one of a firewall, a load balancer, anintrusion prevention system, and a traffic analyzer.
 14. The computerprogram product of claim 8, wherein the network service field ispositioned between the PDU data link layer and network layer of thenon-label switching network.
 15. A system, comprising: one or morenetwork devices of a first enclave of a label switching network, the oneor more devices of the first enclave comprising memory and one or moreprocessors communicatively coupled to the memory, wherein the processorsexecute instructions that are stored in the memory to cause the one ormore network devices of a first enclave to: format a protocol data unit(PDU) of the label switching network to include a network service fieldspecifying at least one network service to be applied to the PDU,wherein the PDU specifies routing and forwarding information of the PDUfor a path in the label switching network ending in an enclave of thelabel switching network other than the first enclave, and routing andforwarding information between enclaves in a non-label switchingnetwork; and communicate the formatted PDU from the first enclave, viathe non-label switching network, to a second enclave of the labelswitching network in accordance with the routing and forwardinginformation between enclaves in the non-label switching network; and oneor more network devices of a second enclave of the label switchingnetwork, the one or more devices of the second enclave comprising memoryand one or more processors communicatively coupled to the memory,wherein the processors execute instructions that are stored in thememory to cause the one or more network devices of a second enclave to:determine from the network service field of the communicated PDU, eachnetwork service specified to be applied to the PDU; apply each of thedetermined network services to the PDU; and transmit the networkserviced PDU in accordance with the routing and forwarding informationof the PDU in the label switching network.
 16. The system of claim 15,wherein the non-label switching network is an Internet Protocol (IP)datagram network, and the network service field describes networkservice chaining.
 17. The system of claim 16, wherein the labelswitching network is a MultiProtocol Label Switching (MPLS) network, andthe network service field is formatted as a network service header(NSH).
 18. The system of claim 17, wherein formatting comprisesformatting a generic routing encapsulation (GRE) field of the non-labelswitching network ahead of the NSH field; and formatting an MPLS labelof the MPLS VPN as a context header in the NSH field.
 19. The system ofclaim 17, wherein formatting comprises formatting a generic routingencapsulation (GRE) field of the non-label switching network, includingan MPLS label of the MPLS VPN, ahead of the NSH field.
 20. The system ofclaim 15, wherein the at least one network service comprises at leastone of a firewall, a load balancer, an intrusion prevention system, anda traffic analyzer.